Now that the leaves are gone one can see them. Large conspicuous stick nests high up in the tree crowns all along the trails down by the North Saskatchewan river. When the trees had leaves the nests were, despite their size, almost impossible to spot. Now, with the leaves gone, one would be hard pressed to miss the nests. The nests are empty as their tenants have moved on on their southward migrations. Who build and occupied these nests? Judging from the size it was likely a larger species, perhaps a corvid such as crows, ravens or jays. Now that I know where the nests are located, I can keep an eye on them next spring to see who moves in (which does not necessarily have to be the same inhabitants as this year).
The North Saskatchewan river is know for its brown and murky water. The color is due naturally occurring sediments that are washed into the river, particularly during he spring melt and during periods of rain. People sometimes assume that the water is dirty, which is not entirely true. Run off from the storm outfalls contributes a large number of pollutants to the rive. In addition to this, people are generally discouraged from consuming fish from the river due to high levels of naturally occurring mercury. On sunny days and if the light is right the river can, however, become a chameleon and change colour. On a late afternoon, as the sun was getting low, I managed to take this picture of the pale blue surface of the river with the reflections of the Walterdale bridge. No brown color on this afternoon.
It was a sunny late afternoon without a cloud in the sky. A gentle cold breeze made it feel colder than what it really was. It was silent down at the North Saskatchewan River except the rustle from the Quaking Aspen leafs. It was easy to spot the Aspen stand as these were the only trees with leaves left on them. As a matter of fact, while all the leaves were golden yellow on color it looked like none of them had been shed yet. Various species of Aspen are the most widely and commonly occurring three species in the northern part of North America.
From a distance The North Saskatchewan river looks like a quaint meandering water serpent. Once you get next to it, however, you quickly realize that the flow is fast and unrelenting. As a result, the river only freezes over completely when the temperature drops extremely low for long periods of time. As I went for walk along the river edge today I came across patches of thin ice along the shore. This first ice of the year is a sure sign of things to come.
On the banks of the North Saskatchewan River there are a large number of outfalls. An outfall is a drainage facility that conveys stormwater into a natural receiving water body (ex. creek, river, etc…). There city has a map online of all the outfall locations and, well, there are quite a few of them. The other day, as I was walking along the southern shore of the North Saskatchewan River I spotted Outfall 23 across the river. I noticed that the water coming out of the culvert was foaming and getting stuck along the shore as it drifted down stream. Foamy water in itself does not necessarily mean that the water is contaminated (see my previous post number 131 on foam lines). This time, however, it was clear that the foam originated from the outfall culvert. Outfalls convey stormwater that has been collect from runoff from impervious surfaces (e.g., roofs and roads) typically from entire neighbourhoods. This means that pollutants from roadways, lawns and roofs are essentially concentrated and discharged at a single point making the outfall a point source for pollution. The water quality in the North Saskatchewan River changes throughout the seasons with high runoff seasons such as spring resulting in more silty and polluted water. A 1994 study found that discharge of stormwater during summer rain storms does affect water quality in the North Saskatchewan River, including increasing levels of heavy metals and fecal coliform bacteria. The same study also found that the composition of invertebrate animals are dramatically affected downstream from Edmonton due to the change in water chemistry as it flows through the city. One of the effects is an increase in the nutrient levels in the river (think lawn fertilizers) which on one hand can augment the food base for the invertebrates but it can also wreck havoc with the levels of disolved oxygen, similarly to lake suffering from eutrophication (nutrient enrichment).
Instead of a nature walk we went on a bike ride today in the Edmonton River Valley. Although no birding was part of the plan I did pack my binoculars and camera in the paniers, just in case we would bump into anything interesting. Sure enough, as we were approaching Quesnell Bridge I spotted these large white birds in the water along the opposite shore. There were not too many options as to what it could be. Five Americans White Pelicans were frolicking in the murky waters of the river. As we were crossing the bridge we got a closer look and I managed to take a few pictures from my high vantage point. This is the first time I have seen pelicans in the river and I guess, for a water bird, the river is probably as good of a place to hang out as any other body of water. Right along the shore where the pelicans were there were some people fishing. Perhaps the fishermen and the pelicans chosen the same location because it is a good fishing spot.